Purification and properties of human placenta arylsulphatase A.

1. Arylsulphatase A (arylsulphate sulphohydrolase E.N. 3.1.6.1) has been purified 7200-fold from human placenta using concanavalin A Sepharose chromatography. 2. Ultracentrifugation studies indicated that the purified enzyme was homogenous with respect to sedimentation coefficient and molecular weight and has a molecular weight of 102000. 3. The purified enzyme could hydrolyze cerebroside 3-sulphate, seminolipid and sulphogalactosylsphingosine under identical conditions. 4. The kinetic parameters for the hydrolysis of all sulphate esters used in the present study were the same. 5. Both seminolipid and sulphogalactosylsphingosine were competitive inhibitors for the hydrolysis of cerebroside-3-sulphate with an inhibition constant of 0.2 mM. 6. Kinetic parameters, metal ion effect and heat inactivation profile of enzyme suggest that the same active site of enzyme is responsible for the hydrolysis of cerebroside 3-sulphate, seminolipid and sulphogalactosylsphingosine.